Sheck Exley is widely known as a cavediving legend and pioneer of our sport.

Exley was an early adapter to the use of helium in his breathing mixture for deep diving. Sadly, this quest to find out just how deep he could dive cost him his life in 1994 Exley during an attempt to dive to 300m in “El Zacatón”, a deep Mexican sinkhole in the state of Tamaulipas.

What nowadays seems like a foolish attempt to break his own deep diving records was the culmination of years of training and extending the limits of human deep cave exploration using artificially mixed gases.

“El Zacaton” is certainly one of the world’s deepest submerged caves but while it is basically only a very deep pit approximately 100km to the Southeast is a much less known fracture cave which might have a potential to be far deeper.

That cave, Nacimiento del Rio Mante, became a playground for Sheck Exley and his dive buddy Paul de Loach in the late 1970’s when they would explore the cave to depths of over 330feet on air.

In the 1983 a European cave diver, Jochen Hasenmayer, unquestionably proofed the advantages of helium for deep cave diving during a solo exploration in the French Fontaine de Vaucluse to a depth of 656 feet (200m).

Whilst Hasenmayer’s dive was only observed by his own wife Barbara, Sheck Exley made big headlines when he subsequently reached a staggering depth of 867 feet (267m) in Mante in 1989.

In 2017 I was fortunate to be invited by my good friends Bruno Espinoca and Fred Devos to join an expedition to Tamaulipas. The objective of the expedition was to survey and document several of the spring caves emerging from the Sierra del Abra mountains including the infamous Nacimiento del Rio Mante.

With so much cave diving history surrounding the place and the chance to dive some world class high flow deep caves it did not take long for me to decide to join.

Mante is certainly a high flow spring cave. The flow has been measured to 8 m3 /sec during dry season, but discharges during storm events occur as high as 250 m3 /sec. The entire cave is characterised as a narrow fracture at the base of the mountain with a perfectly clear spring basin.

During the project we camped the entire week directly in front of the spring which enabled us to conduct several dives in the cave.

All our dive equipment was previously shipped from Quintana Roo to Tamaulipas and during the week we managed several dives in the cave with accurate 3D mapping to over 100m.

Mante surely discharges a lot of water and even reaching the entrance is hard working fighting against the current. From it’s entrance the cave continues as a narrow fracture about 3m wide to a depth of about 20m from where it suddenly drops to a shelf in 55m. From the on the cave just continues the vertically drop at a steep angle and in 100m the narrow rift becomes wider but continues to steeply drop.

Diving in Mante was a bucket list dive and I am super grateful for having been involved in this expedition.

During the week our group mapped and dived several spring caves in the area and made great connections with local explorers and hopefully we will return soon to document more of these magnificent caves.

Some Statistics

-El Zacaton has been mapped to the bottom in -319m.

-Fontaine-de-Vaucluse has a depth of -308m

-Pozzo del Merro in Italy has been mapped to -392m and in 2016 polish cave diver explored Hranicka Propast, Czech Republic to a depth of -404m.

All these depths have been reached by remotely operated vehicles ROV’s.

The depth of Nacimiento del Rio Mante is unknown to this date. Sheck Exley reported the fracture to continuing to descend at a steep angle ….